Cisco Cisco Compression Service Adapter for Cisco 7000 Series Routers 安装指南

DES is a symmetric encryption mechanism. A single encryption key (called a session key) is used to both 
encrypt and decrypt the data. This key must be generated by the participating routers, without sending 
any meaningful data to each other, which might lead a third party (an intruder) into generating the same 
key value. 

Following are the essential parts to network security:

Authenticating routers—a secure network must begin with trusted security devices. This means that 
each encryption device in the network must be authenticated to each other network device to which 
it will send encrypted data. This eliminates the intruder-in-the-middle attack.

Setting encryption policies—including a declaration to networks that are to be encrypted and 
provision for time limits on encrypted sessions.

Connection setup—provide secure connections that are as immune as possible to the effects of 
attackers listening in.

Use of secure encryption keys—define the types of encryption to use over a secure network.

This product performs encryption and is regulated for export by the U.S. Government. Following is 
specific information regarding compliance with U.S. export laws and regulations for encryption 
products:

This product is not authorized for use by persons located outside the United States and Canada that 
do not have export license authority from the U.S. Government.

This product may not be exported outside the U.S. and Canada either by physical or electronic means 
without the prior written approval of the U.S. Government.

Persons outside the U.S. and Canada may not reexport, resell, or transfer this product by either 
physical or electronic means without prior written approval of the U.S. Government.

The ESA (see ) provides the hardware-based encryption mechanisms required to perform data 
encryption in Cisco 7000 family routers in which ESA is installed. The product number is 
SA-Encrypt(=), and the ESA uses a 40-bit or 56-bit Data Encryption Standard (DES), which is 
configurable via the Cisco IOS crypto engine (also called the software (SW) crypto engine). 

The ESA provides data encryption mechanisms using PK technology based on the concept of the 
Protected Entity (PE), and employing the Data Encryption Standard (DES) and the Digital Signature 
Standard (DSS), to ensure secure data and information can be transferred between similarly equipped 
hosts on your network. 

The ESA can be installed in the Cisco 7200 series routers; however, only one ESA can be installed in a 
Cisco 7200 series router. There are no slot restrictions and any chassis slot can be used; however, you 
must observe special requirements. Before installing or removing an ESA from a Cisco 7200 series 
router, refer to the section “

” on page 33.